Speed regulator



Sept: 5, 1939- l F, H. GuLLlKsEN 2,171,747

SPEED REGULATOR Filed March 30, 1937 WlTm-:ssEs: INVENTOR P72717UZ/l/(Sen.

Patented Sept. 5, 1939 SPEED REGULATOR Finn H. Gulliksen, Wilkinsburg,Pa., assigner to Westinghouse Electric & Manufacturing Company, EastPittsburgh, Pa., a corporation of Pennsylvania Application March 30,1937, Serial No. 133,910

11 Claims. (Cl. 172-293) My invention relates to electronic speedregulators and is particularly adapted for governing the speed of amotor in response to variationsv from the speed of a master speedreference 5 means.

In many industrial applications, it is desirable to govern the speed ofone or more motors with reference to the speed of a master motor orspeed reference means to maintain a fixed desired speed relationtherebetween. Such an application, for example, is one in which materialis required to pass through a plurality of machine sections or rollsthat are driven by individual section driving motors that are requiredto run in synchronism, or at a definite speed relation with respect toone another.

An object of my invention is the provision of a speed regulator of theabove indicated character in which the controlled portion is readilyland automatically adjusted in response to variations in the speed of theregulated motor from its desired value. l

Another object of my invention is the provision of anti-hunting meansthat acts promptly in response to` a change in a regulated quantity.

Other objects and advantages of my invention will be apparent from thefollowing description, reference being had to the accompanying drawing,in which the single iigure illustrates circuits and apparatus comprisingone preferred embodiment of the invention.

Referring to the drawing, a regulated motor I is provided having anarmature winding 2 connected to a suitable source of direct currentrepresented by conductors 3 andV 4, and a field winding 5 that isconnected to said source through a resistor 6 and is supplied withenergy in part from said source and in part from rectifying tubes 1, 8and 9 that are controlled in a manner to`be described, The motor I maybe one of a plurality of section driving motors, each driving a roll I2through suitable gearing mechanism' I3. The roll I2 may berepresentative of a plurality of rolls constituting one section of a 45machine, such as a paper making machine, that is desired to drive at acertain speed with respect to a master speed reference means, such asthe alternating-current source driving motors may be similarlycontrolled with respect to the frequency of alter4 ing-current intheconductors I4 in a manner similar to motor I.l l

A suitable alternating-current source represented by conductors I5 isprovided for supplying I4. -Other section windings I6, shown connectedin delta and inductively coupled to the transformer secondary windingsI1 and I8. The windings I1 constituting an anode transformer areconnected in double Y relationship, the outer terminals being con- 5nected to the anodes I9 of the respective rectifying tubes 1, 8 and 9,and the neutral point being connected by conductor 22 leading to ajunction point 23 between the resistor 6 and the motor eld winding 5,the other side of the field winding being connected by conductor 24 tothe cathodes 25 of the tubes 1, 8 and 9. The windings I8 are Y connectedto provide an alternating current ripple in the grid circuit atapproximately 90 displacement from the anode voltage.

A control -transformer 26 is provided having a primary winding 21 thatis connected to be supplied withvenergy from one phase of thealtermating-current conductors I5, and a secondary winding 28 that isconnected to a full-wave rectifier 29 for supplying a unidirectionalvoltage to a resistor 32 that is proportional to the alternating-currentvoltage supplied to the winding 21. The transformer 26 is also providedwith a secondary winding 33 that is connected in circuit to supply aconstant component of voltage to the primary winding 34 of a regulatingtransformer 35. A variable component of voltage is introduced into theprimary circuit of the regulating transformer through a phase shifter 36having secondary winding 31 connected in said circuit and a primarywinding 38 that is connected by conductors 39 to the alternating-currentthree-phase source I5. The inductively related windings 31 and 38 of thephase shifter 36 are relatively movable and are actuated by adifferential mechanism 42 in a manner to be later explained to vary thephase angle of the component introduced thereby. The regulatingtransformer 35 is provided with a secondary winding 43 that suppliesenergy to a full-wave rectifier 44 that supplies a unidirectionalvoltage across a resistor 45 that is a measure of thealterhating-current voltage supplied to the winding 34. A filter circuitrepresented by the condenser 4 46 is provided for eliminating ripples,in the unidirectional potential. The regulating transformer 35 is alsoprovided with a secondary winding 41 that supplies energy to thefull-wavel rectifier 48 for supplying al unidirectional potential 50across the resistor 49 that is also a measure of the potential suppliedto the primary winding 34 of the regulating transformer 35. A filtercircuit represented by the condenser 5I is provided to three-phaseenergy to the transformer primary i eliminate the .unidirectional waveripples.- y I The rectier tubes 1; 8 and 9 are each provided withcontrol grids $2, the potentials of which are controlled by a circuitextending from.

the tube cathodes 25 through conductor 63, the

resistors 32, 45 and 5B in series, then through the respective separatebranches of the Y connected transformer windings I8 to the respectivegrids 62 ci the several tubes 1, 8 and 3. In this grid circuit, it willbe noted that the voltage component supplied by the resistor 32 issubstan tially constant, since it is determined by the voltage of thestandard source I5. The potential across the resistor 45 is a variabledepending upon the voltageimpressed upon Athe primary winding 3l?. ofthe regulating transformer 35. The voltage across the resistor d is zeroso long as the voltage impressed on the regulating transformer 35 isconstant,` and the voltage component from the windings oi the gridtransformer ld introduces an alternating-voltage wave for ring the tubesthat is displaced substantially 90 from the anode voltage supplied bythe anode transformer winding i1 When voltage is supplied to theregulating transformer 35 at a constant potential, the correspondingunidirectional potential across the resistor da supplied by thefull-wave rectier 4S causes a current to flow to charge the 4condenser5i to a predetermined value depending upon the potential across theresistor 45. The potential across the condenser 54 is impressed acrossthe condenser 51 and resistor 53 in series, causing current to ow tocharge the condenser ,51 to a predetermined value. During lthe flow ofcurrent to the condenser 51, upon an increase in potential across thecondenser 54, current flows in one direction throughv the resistor 5i?to make one end thereof more positive than the other, and thus introducea component of voltage into the grid control circuit the value of whichis determined by the rate of change in the voltage across the resistor49. likewise a I decrease inthe potential across the resistor 49 andacross the condenser 54 after the condensers 54 and 51 have beencharged, causes current` to ow from the condenser 51 through theresistor 58 in the opposite direction so that a potential drop existsacross the resistor 58 in a direction opposite to that existing duringthe charg- 'ng oi the condensers 51 and 54 which introduces a componentof voltage into the grid control circuit of opposite polarity to thatintroduced when the condensers are being charged. So long as the chargeon the condensers 54 and 51 remains-constant, substantially no currentows through the resistor 58 and no voltage component is introduced atthis point in the grid control circuit.

A synchronous motor 64 is provided that runs in synchronism with thefrequency of the source I4 which acts as a master speed reference forthe motor l. The motor 54 is connected to a sun gear 65 of themechanical diierential device 42, the opposite sun gear 65 beingconnected regulated motor I.

by a shaft 61 to run in synchronism with the The gears 65 andl 66 meshwith planetary gears 6s mounted on a; rotatable. casing 65 of thedifferential device that is connected through gears 12 and 13 and shaft5 1i to the phase shifting device 36. When the lmotor I is started andbrought up to speed, the

diierential device 42 'and the phase shifter 36 are connected in themanner shown. Solong as the speed of the motor I is maintained at thedesired relationship with respect to the speed ofA the reference motor64, the sun gears 65 and 6B revolve in opposite directions at the samespeed, so that the planetary gears 63 and the casing E5 do not revolveabout the axis of the shaft 6l', thereby maintaining the windings .35and 31 of the phase changing device 38 in a xed position to supply a'constant alternatingcurrent voltage component to the winding 34 of theregulating transformer 35.

A unidirectional grid control voltage of constant value consisting ofthe voltage components across the resistors 32 and 45 isvtherebyimpressed between the cathodes 25 and the grids 62 of the rectiyingtubes 1 8 and 9, upon which is. superimposed the alternating-currentwave of the grid transformer windings it for :tiring the tubes 1, 8 and9 for some predetermined proportion of each positive half cycle tosupply a unidirectional current from the rectiiier tubes 1, 8 and 9through the eld winding 5 of the motor I. So long as the speed of themotor l is maintained at its desired value, the grid potential impressedupon the tubes l, 8 and d and the-current output of these tubes willremain constant. If the speed of the motor i drops below the speed ofthe reference motor 64, the speed of the sun gear 66 correspondinglydecreases with respect to the speed of the Sun gear 65, causing theplanetary gears E3 to revolve about the axis of the shaft S1 and actuatethe gears I2 and 13 to shift the relative position of the windings 35and 31 of the phase shifter 36 to decrease the voltage impressed on theregulating transformer 35, thus correspondingly decreasing theunidirectional voltages across the resistors 45 and 59. The reduction inthe voltage drop across the resistor 45 causes the potential impressedupon the grids 62 of the rectifying tubes 1, 8 and 5 to become lesspositive t'o thereby decrease the current flowing through the severaltubes and the winding 5 of the motor I to cause the speed of the motor Ito increase. The decrease in potential across the resistor 49 causes thepotential across the condenser 54 and the condenser 51 to likewisedecrease, thus causing a current to flow from the condenser 51 throughthe stabilizing resistor 5B in a direction to make the upper end of theresistor 58 more negative than the lower end, and thus further reducingthe potential of the grids 62 of the several tubes 1, 8 and 9 andcausing a more sudden drop in the current through the i'leld winding 5than would otherwise occur. 'Ihe voltage component introduced` into thegrid circuit across the resistor 58 is of short duration, since theVoltage drop across this resistor becomes zero when the potential acrossthe condensers 54 and 51 again become equal to the voltage across theresistor 43, and the discharging current ceases to iiow from thecondenser. The introduction of the voltage component in the grid circuitthrough speed to be more rapid than it otherwise would be, thuspreventing overtravel in the corrective 75- action due to a delayedresponse, during which v shift the'relative positions of the windings 3land 38 of the phase shifter in the opposite direction and increase thevoltage impressed on the regulating transformer 35, and consequently theunidirectional voltage components across the resistors 45 and 49. Theincrease in the voltage component across the resistor 45 causes thegrids 62 of the rectifying tubes 1, 8 and 9 to become more positive withrespect to the anode voltages, thus increasing the current output of thetubes through the field winding 5 of the motor I and causing the speedof the motor I to decrease. The increase in voltage lacross the resistor49 causes a charging current to flow to increase the charge on thecondenser 54, and on the condenser 51, which current fiow causes apotential to be developed across the resistor 58 in a direction to makethe upper end of the resistor more positive than the lower end, to thusfurther increase the positive bias of the grid 62 and correspondinglyincrease the current output from the rectifier tubes 1, 8 and Sthroughthe motor iield winding 5 to effect a more rapid correction in the motorspeed. The earlier introduction of a substantial .corrective force tobring the motor to its desired speed early in the cycle of its departurefrom the desired speed stabilizes the motor speed characteristic thuspreventing it from swinging as far out 'of phase from the master motor6l as it `otherwise would.`

cal energy and rectifier means, means for developing an alternatingcontrol voltage for governing said rectifier means, means for varyingsaid control voltage in accordance with variations in the speed of theregulated motor from its desired value, and anti-hunting meanscomprising a rectifier supplied with energy at a voltage responsive tovariations in the alternating control voltage anda network connected tothe output side of the rectifier for developing a temporary voltagecomponent corresponding to the rate of change in said alternatingcontrol voltage.

2. In a regulator system, an alternating-current powercircuit, adirect-current motor having a field winding, means for regulating thespeed of said motor comprising grid controlled rectifier means forsupplying a unidirectional current to said eld winding, means forcontrolling the current output of said rectifier means in response tovariations in the speed of said motorffrom a desired value, and meansresponsive to the initiation of a change in the current output of saidrectifier means for effecting a further sudden change in current outputof said rectifier in the-A same direction and of short duration.

3. In aregulator system, an alternating-current power circuit, adirect-current motor having a field winding, means for regulating thespeed of said motor comprising lgrid controlled rectier means forsupplying a unidirectional current to said field winding, means for'producing acorrective grid control voltage component for controllingsaid rectifier means that varies in response to variations in the speedof the motor from its desired value, and means fortemporarilyintroducing a further corrective voltage component into said gridcircuit that aids the lastnamed grid control voltage component and thatis a measure of the rate of variations in said grid control voltage.

4. In a regulator system, an alternating-current power circuit, adirect-current motor having a field winding, means for regulating thespeed of said motor comprising grid controlled rectifier means forsupplying a unidirectional current to said field Winding, means forcontrolling the current output of said rectifier means in response tovariations in the speed of said motor from a desired value comprising agrid control circuit and means for supplying unipotential current fromsaid alternating-current source to said grid control circuit, means forvarying the grid potential comprising a master speed reference means anda phase shifter connected to said alternating current source andactuated in response to the differential speed relation between saidspeed reference means and the regulated motor, and means responsive to avariation in the voltage impressed on s-aid grid control circuit foreffecting a further sudden change of short duration in the gridpotential in the same direction.l

5. In a regulator system, an alternating-current power circuit, adirect-current motor having a field winding, 'means for regulating thespeed of 'said motor comprising grid controlled rectifier means forsupplying a unidirectional current to said field winding, means forcontrolling the current output of said rectifier means in response tovariations in the speed of said motor from a desired value comprising agrid control circuit, a plurality of full-wave rectifying means fordeveloping two unipotential voltage components that are each -a measureof the speed of the regulated motor, means for continuously introducingone ofl said voltage components into said grid control circuit, andmeans comprising a network for introducing a temporary voltage surgeinto said grid circuit upon a variation in the other voltage componentin a direction to aid the correction in the motor speed.

6. In-a regulator system, an alternating-current power circuit, adirect-current motor having a field winding, means for regulating thespeed of said motor comprising grid controlled rectifier means forsupplying a unidirectional current to said field winding, means forcontrolling the current output of said rectifier means in response tovariations in the speed of said motor from a desired value comprising a'grid control circuit, a regulating transformer supplied with energy fromsaid alternating-current source, a'phase shifter in circuit with theprimary winding of said regulating transformer, 'and means for actuatingsaid `phase shifter in response to variations in the speed of theregulated motor from its desired value, a plurality of rectifying meanssupplied with energy from said regulating transformer for producingunidirectional voltage components responsive to the voltage supplied tosaid regulating transformer, means for continuously introducing one ofsaid voltage components into said grid control circuit, and meanscomprising `a network for introducing a temporary voltage surge intosaid grid circuit upon a variation in the other `voltage component in adirection to aid the correction in the motor speed.

7. In a speed regulator system, in combination, a 4direct-current motorto be regulated having a eld winding, means for supplying energy'to saidfield winding comprising an alternating-current source of electricalenergy and grid-controlled rectifier means, a grid control circuit 'forsaid rectifier means, means including a source of -alternating controlvoltage and a plurality of rectifier means for introducingunidirectional voltage components into said grid control circuit, one ofsaid unidirectional voltage* components varying with variations in saidalternating control voltage in a vdirection to effect a correction inthe motor speed, another of said unidirectional voltage componentsvarying with the direction and degree of voltage change in thealternating control voltage, also in a direction to eiiect a correctionin the motor speed, and means for varying said alternating controlvolt-s age in accordance with variations in the speed of the regulatedmotor from its desired value.

8. In a speed regulator system, in combination, a direct-current motorto be regulated having a iield winding, means for supplying energy tosaid iield winding comprising an alternating-current source ofelectrical energy and grid-controlled rectifier means, means fordeveloping a grid control voltage for governing said rectier meanscomprising a source of alternating control voltage and a plurality ofrecter means for developing unidirectional voltages that vary withvariations in said alternating control voltage, one of said rectiermeans being connected to introduce its developed unidirectional voltageinto said grid control circuit, another of said rectiner means beingconnected to an anti-hunting net- Work for introducing a potential intosaid grid control circuit that varies in amount and direction withvariations in said alternating control voltage, and means for varyingsaid alternating control voltage in accordance with variations in thespeed of the regulated motor from its desired value.

9. In a regulator system, an alternating-current power circuit, adirect-current motor having a iield winding, means for regulating thespeed of said motor comprising grid-controlled rectiiier means forsupplying a. unidirectional current to said eld winding, meansfor con'trolling the current output of said rectifier means in response tovariations of the speed of said motor from a desired value including agrid control circuit and means for introducing unidirectional voltagecomponents into said grid-con'- trolled circuit vfrom saidalternating-current source comprising a phase shifter for developing avariable control alternating voltage and a pair of rectiiier means, oneof said rectier means being connected to introduce its developedunidirectional voltage directly int'o said grid control circuit, and theother of said rectiiier means being connected to an anti-hunting networkto introduce a potential into said grid control circuit that varies inamount and direction with variations Vin said control alternatingvoltage, and

fmeans for actuating said phase shifter comprising a speed referencemeans and diierential. mechanism responsive to the differential speedsof said regulated motor and said speed reference means.

10. In a regulator system, an alternating-current power circuit, adirect-current motor having a eld winding and an armature winding, adirect-'current source of power for supplying energy to saiddirect-current motor, means for governing the excitation ot said motorto regulate the motor speed comprising a grid controlled rectier means,means for controlling the current output of said rectier meansinresponse to variations in the speed of 'said motor from a desired valuecomprising a grid control circuit, a;

plurality of full-wave rectifying means for developing unipotentialvoltage components that are each a measure of the speed of the regulatedmotor, means for continuously introducing one of said voltage componentsinto said grid control circuit, and means comprising a. network forintroducing a temporary voltage surge into said grid circuit upon avariation in angther of said voltage components in a direction to aidthe correction in the motor speed.

11. In a regulator system, an alternating-current power circuit, adirect-current motor having a eld winding and an armature winding, adirectecurrent source of power for supplying energy to said.direct-current motor, lmeans for governing the excitation of said motorto regulate the motor speed comprising a grid controlled rectier means,means for controlling the current output of said rectier means inresponse to variations inthe speed of said motor from a desired valuecomprising a grid control circuit, a regulating transformer suppliedwith energy from said alternating-current source, a phase shifteriii-circuit with the, primary Winding of said regulating transformer,and means ior actuating said phase shifter in response to variations inthe speed ofthe regulated motor from its desired value, a plurality ofrectifying means supplied with energy from said regulating transformerfor producing unidirectional voltage components responsive to thevoltage supplied to said regulating transformer, means for continuouslyintroducing oneof said voltage components into said grid controlcircuit, and means comprising a network for introducing a temporaryvoltage surge into said grid circuit upon a variation in the othervoltage component in a direction to aid the correction in the motorspeed.

FINN H. GUILIKSEN.

